The card shows an example result of 190 U·L⁻¹, which is 2.67 SD above the mean.

What it measures

Creatine kinase helps muscle cells store and use energy. The MM form comes almost entirely from skeletal muscle and leaks into the blood when muscle fibres are damaged.

Reference range

The mean is (low + high) / 2 and the SD is (high − low) / 4, so the healthy range covers Z from −2 to +2.

Reading the result

• High — Points to muscle damage, from hard training, injury, certain medicines such as statins, or a muscle disease.
• Low — Not a concern. Low values can reflect low muscle mass.

Notes

• Strenuous exercise can raise it for several days. Avoid hard training for 48 to 72 hours before the test.
• Muscle mass, sex, and ancestry all affect the usual level.
• This page is general information, not medical advice. Discuss results with a clinician.